When displaying an image, a display device needs to utilize a shift register to scan pixel units. A shift register comprises multiple shift register units, and each of the shift register units corresponds to a row of pixel units. The multiple shift register units implement progressive scan driving of the pixel units of a display device to display an image.
As the number of pixels increases, the number of rows which the shift register (a gate switch circuit) needs to scan in a frame of time increases, which requires that the layout area of a shift register unit be less and its circuit structure be simpler. Generally, a shift register unit controls the size of the potential of the output signal of the circuit by multiple transistors and capacitors. However, in such a case, the circuit structure of each of the shift register units is relatively complex, and the control process is relatively cumbersome.